From the time of the first sewing machine, the needle bar and the feeding means have been moved by means of mechanical devices, such as eccentrics, linkage-systems, cam plates and cam followers. As the technique in the design of sewing machines has enabled sewing patterns of an increasing complexity to be performed, so have the mechanical devices required in connection herewith become more complicated and expensive to manufacture. To enable a more versatile machine to be developed, it has been necessary to provide alternatives to the before-mentioned mechanical devices, these devices hitherto being the only auxiliary devices provided for effecting the movements of the pattern-forming devices.